Metal complex for phosphorescent oled

ABSTRACT

The present invention relates to novel iridium complexes that can be used in organic light emitting devices (OLEDs). The present invention relates to the iridium complexes, devices comprising the iridium complexes, and formulations comprising the iridium complexes.

This application is a non-provisional of U.S. Provisional ApplicationNo. 61/916,552, filed Dec. 16, 2013. The disclosure of which isincorporated by reference in its entirety.

The claimed invention was made by, on behalf of, and/or in connectionwith one or more of the following parties to a joint universitycorporation research agreement: Regents of the University of Michigan,Princeton University. The University of Southern California, and theUniversal Display Corporation. The agreement was in effect on and beforethe date the claimed invention was made, and the claimed invention wasmade as a result of activities undertaken within the scope of theagreement.

FIELD OF THE INVENTION

The present invention relates to novel iridium complexes that can beused in organic light emitting devices (OLEDs). The present inventionrelates to the iridium complexes, devices comprising the iridiumcomplexes, and formulations comprising the iridium complexes.

BACKGROUND

Opto-electronic devices that make use of organic materials are becomingincreasingly desirable for a number of reasons. Many of the materialsused to make such devices are relatively inexpensive, so organicopto-electronic devices have the potential for cost advantages overinorganic devices. In addition, the inherent properties of organicmaterials, such as their flexibility, may make them well suited forparticular applications such as fabrication on a flexible substrate.Examples of organic opto-electronic devices include organic lightemitting devices, organic phototransistors, organic photovoltaic cells,and organic photodetectors. For OLEDs, the organic materials may haveperformance advantages over conventional materials. For example, thewavelength at which an organic emissive layer emits light may generallybe readily tuned with appropriate dopants.

OLEDs make use of thin organic films that emit light when voltage isapplied across the device. OLEDs are becoming an increasinglyinteresting technology for use in applications such as flat paneldisplays, illumination, and backlighting. Several OLED materials andconfigurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and5,707,745, which are incorporated herein by reference in their entirety.

One application for phosphorescent emissive molecules is a full colordisplay. Industry standards for such a display call for pixels adaptedto emit particular colors, referred to as “saturated” colors. Inparticular, these standards call for saturated red, green, and bluepixels. Color may be measured using CIE coordinates, which are wellknown to the art.

One example of a green emissive molecule is tris(2-phenylpyridine)iridium, denoted Ir(ppy)₃, which has the following structure:

In this, and later figures herein, we depict the dative bond fromnitrogen to metal (here, Ir) as a straight line.

As used herein, the term “organic” includes polymeric materials as wellas small molecule organic materials that may be used to fabricateorganic opto-electronic devices. “Small molecule” refers to any organicmaterial that is not a polymer, and “small molecules” may actually bequite large. Small molecules may include repeat units in somecircumstances. For example, using a long chain alkyl group as asubstituent does not remove a molecule from the “small molecule” class.Small molecules may also be incorporated into polymers, for example as apendent group on a polymer backbone or as a part of the backbone. Smallmolecules may also serve as the core moiety of a dendrimer, whichconsists of a series of chemical shells built on the core moiety. Thecore moiety of a dendrimer may be a fluorescent or phosphorescent smallmolecule emitter. A dendrimer may be a “small molecule,” and it isbelieved that all dendrimers currently used in the field of OLEDs aresmall molecules.

As used herein, “top” means furthest away from the substrate, while“bottom” means closest to the substrate. Where a first layer isdescribed as “disposed over” a second layer, the first layer is disposedfurther away from substrate. There may be other layers between the firstand second layer, unless it is specified that the first layer is “incontact with” the second layer. For example, a cathode may be describedas “disposed over” an anode, even though there are various organiclayers in between.

As used herein, “solution processable” means capable of being dissolved,dispersed, or transported in and/or deposited from a liquid medium,either in solution or suspension form.

A ligand may be referred to as “photoactive” when it is believed thatthe ligand directly contributes to the photoactive properties of anemissive material. A ligand may be referred to as “ancillary” when it isbelieved that the ligand does not contribute to the photoactiveproperties of an emissive material, although an ancillary ligand mayalter the properties of a photoactive ligand.

As used herein, and as would be generally understood by one skilled inthe art, a first “Highest Occupied Molecular Orbital” (HOMO) or “LowestUnoccupied Molecular Orbital” (LUMO) energy level is “greater than” or“higher than” a second HOMO or LUMO energy level if the first energylevel is closer to the vacuum energy level. Since ionization potentials(IP) are measured as a negative energy relative to a vacuum level, ahigher HOMO energy level corresponds to an IP having a smaller absolutevalue (an IP that is less negative). Similarly, a higher LUMO energylevel corresponds to an electron affinity (EA) having a smaller absolutevalue (an EA that is less negative). On a conventional energy leveldiagram, with the vacuum level at the top, the LUMO energy level of amaterial is higher than the HOMO energy level of the same material. A“higher” HOMO or LUMO energy level appears closer to the top of such adiagram than a “lower” HOMO or LUMO energy level.

As used herein, and as would be generally understood by one skilled inthe art, a first work function is “greater than” or “higher than” asecond work function if the first work function has a higher absolutevalue. Because work functions are generally measured as negative numbersrelative to vacuum level, this means that a “higher” work function ismore negative. On a conventional energy level diagram, with the vacuumlevel at the top, a “higher” work function is illustrated as furtheraway from the vacuum level in the downward direction. Thus, thedefinitions of HOMO and LUMO energy levels follow a different conventionthan work functions.

More details on OLEDs, and the definitions described above, can be foundin U.S. Pat. No. 7,279,704, which is incorporated herein by reference inits entirety.

BRIEF SUMMARY OF THE INVENTION

A new class of heteroleptic Ir(III) complexes are provided.

The present invention provides compounds of formula I:

(L_(A))_(m)Ir(L_(B))_(3-m)  (I).

In the compound of formula I, L_(A) is

L_(B) is selected from the group consisting of:

R_(E) represents mono or di-substitution, or no substitution; R², R_(A),and R_(D) are each independently mono, di, or tri-substitution, or nosubstitution; R¹, R_(B), R_(C), and R_(F) are each independently mono,di, tri, or tetra-substitution, or no substitution; X¹, X², X³, X⁴, andX⁵ are each independently carbon or nitrogen; X is selected from thegroup consisting of O, S, and Se; R¹, R², R_(A), R_(B), R_(C), R_(D),R_(E), and R_(F) are each independently selected from the groupconsisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,carboxylic acid, ester, nitrite, isonitrile, sulfanyl, sulfinyl,sulfonyl, phosphino, and combinations thereof; R³ is selected from thegroup consisting of alkyl, cycloalkyl, and combinations thereof; R³ isoptionally partially or fully deuterated; and m is 1 or 2.

In some embodiments, m is 2.

In some embodiments, X is O.

In some embodiments, R³ is an alkyl having at least 2 carbons.

In some embodiments, R³ is an alkyl having at least 3 carbons.

In some embodiments, R³ is a cycloalkyl.

In some embodiments, R³ is selected from the group consisting of methyl,ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl,pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl,1,2-dimethylpropyl, 2,2-dimethylpropyl, cyclopentyl, and cyclohexyl,wherein each is optionally partially or fully deuterated.

In some embodiments, R¹ is selected from the group consisting ofhydrogen, deuterium, alkyl, cycloalkyl, and combinations thereof.

In some embodiments, R² represents no substitution.

In some embodiments, R_(F) is selected from the group consisting ofhydrogen, deuterium, alkyl, cycloalkyl, halogen, and combinationsthereof. In some embodiments, R_(F) is fluorine.

In some embodiments, R_(C), R_(D), and R_(E) each represent nosubstitution.

In some embodiments, L_(B) is selected from the group consisting of:

In some embodiments, L_(B) is:

wherein R_(G) represents mono, di, tri, or tetra-substitution, or nosubstitution; and wherein R_(G) is selected from the group consisting ofhydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof.

In some embodiments wherein L_(B) is formula VI, R_(B) and R_(E)represent no substitution; and R_(F) and R_(G) are each independentlyselected from the group consisting of hydrogen, deuterium, alkyl,cycloalkyl, halogen, and combinations thereof. In some embodimentswherein L_(B) is formula VI, R_(G) is fluorine.

In some embodiments, L_(A) is selected from the group consisting ofL_(A1) to L_(A86).

In some embodiments, L_(B) is selected from the group consisting ofL_(B1) to L_(B259).

In some embodiments, the compound of formula I is selected from thegroup consisting of Compound I-1 to Compound I-15.

In some embodiments, a first device is provided. The first devicecomprises an anode, a cathode, and an organic layer, disposed betweenthe anode and the cathode, comprising a compound having the formula:

(L_(A))_(m)Ir(L_(B))_(3-m)  (I).

In the compound of formula I, L_(A) is

L_(B) is selected from the group consisting of:

R_(E) represents mono or di-substitution, or no substitution; R², R_(A),and R_(D) are each independently mono, di, or tri-substitution, or nosubstitution; R¹, R_(B), R_(C), and R_(F) are each independently mono,di, tri, or tetra-substitution, or no substitution; X¹, X², X³, X⁴, andX⁵ are each independently carbon or nitrogen; X is selected from thegroup consisting of O, S, and Se; R¹, R², R_(A), R_(B), R_(C), R_(D),R_(E), and R_(F) are each independently selected from the groupconsisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl,sulfonyl, phosphino, and combinations thereof; R³ is selected from thegroup consisting of alkyl, cycloalkyl, and combinations thereof; R³ isoptionally partially or fully deuterated; and m is 1 or 2.

In some embodiments, the first device is a consumer product.

In some embodiments, the first device is an organic light-emittingdevice.

In some embodiments, the first device comprises a lighting panel.

In some embodiments, the organic layer of the first device is anemissive layer and the compound is an emissive dopant. In someembodiments, the organic layer of the first device is an emissive layerand the compound is a non-emissive dopant.

In some embodiments, the organic layer of the first device furthercomprises a host.

In some embodiments, the host of the first device comprises atriphenylene containing benzo-fused thiophene or benzo-fused furan;wherein any substituent in the host is an unfused substituentindependently selected from the group consisting of C_(n)H_(2n+1),OC_(n)H_(2n+1), OAr₁, N(C_(n)H_(2n+1))₂, N(Ar₁)(Ar₂),CH═CH—C_(n)H_(2n+1), C≡CC_(n)H_(2n+1), Ar₁, Ar₁-Ar₂, C_(n)H_(2n)-Ar₁, orno substitution; wherein n is from 1 to 10; and wherein Ar₁ and Ar₂ areindependently selected from the group consisting of benzene, biphenyl,naphthalene, triphenylene, carbazole, and heteroaromatic analogsthereof.

In some embodiments, the host of the first device comprises at least onechemical group selected from the group consisting of carbazole,dibenzothiophene, dibenzofuran, dibenzoselenophene, azacarbazole,aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene.

In some embodiments, the host is selected from the group consisting of:

and combinations thereof.

In some embodiments, the host of the first device comprises a metalcomplex.

In some embodiments, a formulation comprising a compound of formula I isprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and form a partof the specification, illustrate embodiments of the present inventionand, together with the description, further serve to explain theprinciples of the invention and to enable a person skilled in thepertinent art to make and use the invention.

FIG. 1 shows an organic light emitting device.

FIG. 2 shows an inverted organic light emitting device that does nothave a separate electron transport layer.

FIG. 3 shows a compound of Formula I-A.

FIG. 4 shows a compound of Formula I-B.

FIG. 5 shows a compound of Formula I-C.

DETAILED DESCRIPTION

Generally, an OLED comprises at least one organic layer disposed betweenand electrically connected to an anode and a cathode. When a current isapplied, the anode injects holes and the cathode injects electrons intothe organic layer(s). The injected holes and electrons each migratetoward the oppositely charged electrode. When an electron and holelocalize on the same molecule, an “exciton,” which is a localizedelectron-hole pair having an excited energy state, is formed. Light isemitted when the exciton relaxes via a photoemissive mechanism. In somecases, the exciton may be localized on an excimer or an exciplex.Non-radiative mechanisms, such as thermal relaxation, may also occur,but are generally considered undesirable.

The initial OLEDs used emissive molecules that emitted light from theirsinglet states (“fluorescence”) as disclosed, for example, in U.S. Pat.No. 4,769,292, which is incorporated by reference in its entirety.Fluorescent emission generally occurs in a time frame of less than 10nanoseconds.

More recently, OLEDs having emissive materials that emit light fromtriplet states (“phosphorescence”) have been demonstrated. Baldo et al.,“Highly Efficient Phosphorescent Emission from OrganicElectroluminescent Devices,” Nature, vol. 395, 151-154, 1998;(“Baldo-I”) and Baldo et al., “Very high-efficiency green organiclight-emitting devices based on electrophosphorescence,” Appl. Phys.Lett., vol. 75, No. 3, 4-6 (1999) (“Baldo-H”), which are incorporated byreference in their entireties. Phosphorescence is described in moredetail in U.S. Pat. No. 7,279,704 at cols. 5-6, which are incorporatedby reference.

FIG. 1 shows an organic light emitting device 100. The figures are notnecessarily drawn to scale. Device 100 may include a substrate 110, ananode 115, a hole injection layer 120, a hole transport layer 125, anelectron blocking layer 130, an emissive layer 135, a hole blockinglayer 140, an electron transport layer 145, an electron injection layer150, a protective layer 155, a cathode 160, and a barrier layer 170.Cathode 160 is a compound cathode having a first conductive layer 162and a second conductive layer 164. Device 100 may be fabricated bydepositing the layers described, in order. The properties and functionsof these various layers, as well as example materials, are described inmore detail in U.S. Pat. No. 7,279,704 at cols. 6-10, which areincorporated by reference.

More examples for each of these layers are available. For example, aflexible and transparent substrate-anode combination is disclosed inU.S. Pat. No. 5,844,363, which is incorporated by reference in itsentirety. An example of a p-doped hole transport layer is m-MTDATA dopedwith F₄-TCNQ at a molar ratio of 50:1, as disclosed in U.S. PatentApplication Publication No. 2003/0230980, which is incorporated byreference in its entirety. Examples of emissive and host materials aredisclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which isincorporated by reference in its entirety. An example of an n-dopedelectron transport layer is BPhen doped with Li at a molar ratio of 1:1,as disclosed in U.S. Patent Application Publication No. 2003/0230980,which is incorporated by reference in its entirety. U.S. Pat. Nos.5,703,436 and 5,707,745, which are incorporated by reference in theirentireties, disclose examples of cathodes including compound cathodeshaving a thin layer of metal such as Mg:Ag with an overlyingtransparent, electrically-conductive, sputter-deposited ITO layer. Thetheory and use of blocking layers is described in more detail in U.S.Pat. No. 6,097,147 and U.S. Patent Application Publication No.2003/0230980, which are incorporated by reference in their entireties.Examples of injection layers are provided in U.S. Patent ApplicationPublication No. 2004/0174116, which is incorporated by reference in itsentirety. A description of protective layers may be found in U.S. PatentApplication Publication No. 2004/0174116, which is incorporated byreference in its entirety.

FIG. 2 shows an inverted OLED 200. The device includes a substrate 210,a cathode 215, an emissive layer 220, a hole transport layer 225, and ananode 230. Device 200 may be fabricated by depositing the layersdescribed, in order. Because the most common OLED configuration has acathode disposed over the anode, and device 200 has cathode 215 disposedunder anode 230, device 200 may be referred to as an “inverted” OLED.Materials similar to those described with respect to device 100 may beused in the corresponding layers of device 200. FIG. 2 provides oneexample of how some layers may be omitted from the structure of device100.

The simple layered structure illustrated in FIGS. 1 and 2 is provided byway of non-limiting example, and it is understood that embodiments ofthe invention may be used in connection with a wide variety of otherstructures. The specific materials and structures described areexemplary in nature, and other materials and structures may be used.Functional OLEDs may be achieved by combining the various layersdescribed in different ways, or layers may be omitted entirely, based ondesign, performance, and cost factors. Other layers not specificallydescribed may also be included. Materials other than those specificallydescribed may be used. Although many of the examples provided hereindescribe various layers as comprising a single material, it isunderstood that combinations of materials, such as a mixture of host anddopant, or more generally a mixture, may be used. Also, the layers mayhave various sublayers. The names given to the various layers herein arenot intended to be strictly limiting. For example, in device 200, holetransport layer 225 transports holes and injects holes into emissivelayer 220, and may be described as a hole transport layer or a holeinjection layer. In some embodiments, an OLED may be described as havingan “organic layer” disposed between a cathode and an anode. This organiclayer may comprise a single layer, or may further comprise multiplelayers of different organic materials as described, for example, withrespect to FIGS. 1 and 2.

Structures and materials not specifically described may also be used,such as OLEDs comprised of polymeric materials (PLEDs) such as disclosedin U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated byreference in its entirety. By way of further example, OLEDs having asingle organic layer may be used. OLEDs may be stacked, for example asdescribed in U.S. Pat. No. 5,707,745 to Forrest et al, which isincorporated by reference in its entirety. The OLED structure maydeviate from the simple layered structure illustrated in FIGS. 1 and 2.For example, the substrate may include an angled reflective surface toimprove out-coupling, such as a mesa structure as described in U.S. Pat.No. 6,091,195 to Forrest et al., and/or a pit structure as described inU.S. Pat. No. 5,834,893 to Bulovic et al., which are incorporated byreference in their entireties.

Unless otherwise specified, any of the layers of the various embodimentsmay be deposited by any suitable method. For the organic layers,preferred methods include thermal evaporation, ink-jet, such asdescribed in U.S. Pat. Nos. 6,013,982 and 6,087,196, which areincorporated by reference in their entireties, organic vapor phasedeposition (OVPD), such as described in U.S. Pat. No. 6,337,102 toForrest et al., which is incorporated by reference in its entirety, anddeposition by organic vapor jet printing (OVJP), such as described inU.S. Pat. No. 7,431,968, which is incorporated by reference in itsentirety. Other suitable deposition methods include spin coating andother solution based processes. Solution based processes are preferablycarried out in nitrogen or an inert atmosphere. For the other layers,preferred methods include thermal evaporation. Preferred patterningmethods include deposition through a mask, cold welding such asdescribed in U.S. Pat. Nos. 6,294,398 and 6,468,819, which areincorporated by reference in their entireties, and patterning associatedwith some of the deposition methods such as ink-jet and OVJP. Othermethods may also be used. The materials to be deposited may be modifiedto make them compatible with a particular deposition method. Forexample, substituents such as alkyl and aryl groups, branched orunbranched, and preferably containing at least 3 carbons, may be used insmall molecules to enhance their ability to undergo solution processing.Substituents having 20 carbons or more may be used, and 3-20carbons is apreferred range. Materials with asymmetric structures may have bettersolution processability than those having symmetric structures, becauseasymmetric materials may have a lower tendency to recrystallize.Dendrimer substituents may be used to enhance the ability of smallmolecules to undergo solution processing.

Devices fabricated in accordance with embodiments of the presentinvention may further optionally comprise a barrier layer. One purposeof the barrier layer is to protect the electrodes and organic layersfrom damaging exposure to harmful species in the environment includingmoisture, vapor and/or gases, etc. The barrier layer may be depositedover, under or next to a substrate, an electrode, or over any otherparts of a device including an edge. The barrier layer may comprise asingle layer, or multiple layers. The barrier layer may be formed byvarious known chemical vapor deposition techniques and may includecompositions having a single phase as well as compositions havingmultiple phases. Any suitable material or combination of materials maybe used for the barrier layer. The barrier layer may incorporate aninorganic or an organic compound or both. The preferred barrier layercomprises a mixture of a polymeric material and a non-polymeric materialas described in U.S. Pat. No. 7,968,146, PCT Pat. Application Nos.PCT/US2007/023098 and PCT/US2009/042829, which are herein incorporatedby reference in their entireties. To be considered a “mixture”, theaforesaid polymeric and non-polymeric materials comprising the barrierlayer should be deposited under the same reaction conditions and/or atthe same time. The weight ratio of polymeric to non-polymeric materialmay be in the range of 95:5 to 5:95. The polymeric material and thenon-polymeric material may be created from the same precursor material,in one example, the mixture of a polymeric material and a non-polymericmaterial consists essentially of polymeric silicon and inorganicsilicon.

Devices fabricated in accordance with embodiments of the invention maybe incorporated into a wide variety of consumer products, including flatpanel displays, computer monitors, medical monitors, televisions,billboards, lights for interior or exterior illumination and/orsignaling, heads up displays, fully transparent displays, flexibledisplays, laser printers, telephones, cell phones, personal digitalassistants (PDAs), laptop computers, digital cameras, camcorders,viewfinders, micro-displays, 3-D displays, vehicles, a large area wall,theater or stadium screen, or a sign. Various control mechanisms may beused to control devices fabricated in accordance with the presentinvention, including passive matrix and active matrix. Many of thedevices are intended for use in a temperature range comfortable tohumans, such as 18 degrees C. to 30 degrees C., and more preferably atroom temperature (20-25 degrees C.), but could be used outside thistemperature range, for example, from −40 degree C. to +80 degrees C.

The materials and structures described herein may have applications indevices other than OLEDs. For example, other optoelectronic devices suchas organic solar cells and organic photodetectors may employ thematerials and structures. More generally, organic devices, such asorganic transistors, may employ the materials and structures.

The term “halo” or “halogen” as used herein includes fluorine, chlorine,bromine and iodine.

The term “alkyl” as used herein contemplates both straight and branchedchain alkyl radicals. Preferred alkyl groups are those containing fromone to fifteen carbon atoms and includes methyl, ethyl, propyl,isopropyl, butyl, isobutyl, tert-butyl, and the like. Additionally, thealkyl group may be optionally substituted.

The term “cycloalkyl” as used herein contemplates cyclic alkyl radicals.Preferred cycloalkyl groups are those containing 3 to 7 carbon atoms andincludes cyclopropyl, cyclopentyl, cyclohexyl, and the like.Additionally, the cycloalkyl group may be optionally substituted.

The term “alkenyl” as used herein contemplates both straight andbranched chain alkene radicals. Preferred alkenyl groups are thosecontaining two to fifteen carbon atoms. Additionally, the alkenyl groupmay be optionally substituted.

The term “alkynyl” as used herein contemplates both straight andbranched chain alkyne radicals. Preferred alkyl groups are thosecontaining two to fifteen carbon atoms. Additionally, the alkynyl groupmay be optionally substituted.

The terms “aralkyl” or “arylalkyl” as used herein contemplates an alkylgroup that has as a substituent an aromatic group. Additionally, thearalkyl group may be optionally substituted.

The term “heterocyclic group” as used herein contemplates non-aromaticcyclic radicals. Preferred heterocyclic groups are those containing 3 or7 ring atoms which includes at least one hetero atom, and includescyclic amines such as morpholino, piperdino, pyrrolidino, and the like,and cyclic ethers, such as tetrahydrofuran, tetrahydropyran, and thelike. Additionally, the heterocyclic group may be optionallysubstituted.

The term “aryl” or “aromatic group” as used herein contemplatessingle-ring groups and polycyclic ring systems. The polycyclic rings mayhave two or more rings in which two carbons are common by two adjoiningrings (the rings are “fused”) wherein at least one of the rings isaromatic, e.g., the other rings can be cycloalkyls, cycloalkenyls, aryl,heterocycles and/or heteroaryls. Additionally, the aryl group may beoptionally substituted.

The term “heteroaryl” as used herein contemplates single-ringhetero-aromatic groups that may include from one to three heteroatoms,for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole,triazole, pyrazole, pyridine, pyrazine and pyrimidine, and the like. Theterm heteroaryl also includes polycyclic hetero-aromatic systems havingtwo or more rings in which two atoms are common to two adjoining rings(the rings are “fused”) wherein at least one of the rings is aheteroaryl, e.g., the other rings can be cycloalkyls, cycloalkenyls,aryl, heterocycles and/or heteroaryls. Additionally, the heteroarylgroup may be optionally substituted.

The alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclic group,aryl, and heteroaryl may be optionally substituted with one or moresubstituents selected from the group consisting of hydrogen, deuterium,halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile,sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.

As used herein, the term “substituted” indicates that a substituentother than hydrogen is bonded to the relevant carbon or nitrogen atom.Thus, where R¹ is mono-substituted, then one R¹ must be other thanhydrogen. Similarly, where R¹ is di-substituted, then two of R¹ must beother than hydrogen. Similarly, where R¹ “represents no substitution,”R¹ is hydrogen for all available positions.

Compounds are provided comprising a heteroleptic k(III) complex havingextended conjugation. Heteroleptic iridium complexes are of greatinterest because their photophysical, thermal, and electronic propertiescan be tuned according to the ligands that are attached to the metalcenter. One advantage to using heteroleptic iridium complexes is thatthey offer improved device lifetime and a lower sublimation temperature,therefore offering improved manufacturing, as compared to homolepticIr(III) complexes. For example, a heteroleptic complex containing2-phenylpyridine and 2-(biphenyl-3-yl)pyridine, has shown an improvedlifetime compared to a related homoleptic complex. Further, thesublimation temperature of the heteroleptic complex is almost 70° C.lower than the homoleptic complex. See, U.S. Pat. No. 8,119,255.Heteroleptic complexes which demonstrate improved stability and lowsublimation temperatures, such as those disclosed herein, are highlydesirable for use in OLEDs. In particular, the heteroleptic Ir(III)complexes may be especially desirable for use in white organic lightemitting devices (WOLEDs).

Iridium complexes containing alkyl substituted 2-phenylpyridine ligandshave been used as emitters in phosphorescent OLEDs. Alkyl substitutionat the 4-position on the phenyl ring of the 2-phenylpyridine ligandnormally reduces the device efficiency. For example, devices withtris(2-(5-methyl-phenyl)pyridine)iridium(III) showed much lower externalquantum efficiency (EQE) compared to tris(2-phenylpyridine)iridium(III).In the same device structure using4,4′-di(9H-carbazol-9-yl)-1,1′-biphenyl (CBP) as host with 12% emitterdoping concentration, a device withtris(2-(5-methyl-phenyl)pyridine)iridium(III) showed an EQE of 6.6%,whereas the device with tris(2-phenylpyridine)iridium(III) showed an EQEof 9.0%. Therefore, introduction of alkyl substitution at this positionis not considered desirable. In the present invention, it was discoveredthat 4-alkyl substitution on the phenyl ring of the phenylpyridineligand can improved device EQE in heteroleptic complexes.

In some embodiments, a compound having the formula:

(L_(A))_(m)Ir(L_(B))_(3-m)  (I);

is provided. In the compound of formula I, L_(A) is

L_(B) is selected from the group consisting of:

R_(E) represents mono or di-substitution, or no substitution; R², R_(A),and R_(D) are each independently mono, di, or tri-substitution, or nosubstitution; R¹, R_(B), R_(C), and R_(F) are each independently mono,di, tri, or tetra-substitution, or no substitution; X¹, X², X³, X⁴, andX⁵ are each independently carbon or nitrogen; X is selected from thegroup consisting of O, S, and Se; R¹, R², R_(A), R_(B), R_(C), R_(D),R_(E), and R_(F) are each independently selected from the groupconsisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl,sulfonyl, phosphino, and combinations thereof; R³ is selected from thegroup consisting of alkyl, cycloalkyl, and combinations thereof; R³ isoptionally partially or fully deuterated; and m is 1 or 2.

In some embodiments, L_(B) is selected from the group consisting of:

In some embodiments, L_(B) is:

wherein R_(G) represents mono, di, tri, or tetra-substitution, or nosubstitution; and wherein R_(G) is selected from the group consisting ofhydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof.

In some embodiments where L_(B) is formula (VI), R_(B) and R_(E)represent no substitution; and R_(F) and R_(G) are each independentlyselected from the group consisting of hydrogen, deuterium, alkyl,cycloalkyl, halogen, and combinations thereof. In some embodiments whereL_(B) is formula (VI), R_(G) is fluorine.

In some embodiments, L_(A) is selected from the group consisting ofL_(A1) to L_(A86) listed below:

In some embodiments, L_(A) is selected from the group consisting ofL_(A87) to L_(A172) listed below:

In some embodiments, L_(A) is selected from the group consisting ofL_(A1), L_(A2), L_(A3), L_(A4), L_(A5), and L_(A61). In someembodiments, L_(A) is L_(A1). In some embodiments, L_(A) is L_(A2). Insome embodiments, L_(A) is L_(A3). In some embodiments, L_(A) is L_(A4).In some embodiments, L_(A) is L_(A5). In some embodiments, L_(A) isL_(A61).

In some embodiments, L_(B) is selected from the group consisting ofL_(B1) to L_(B259) listed below:

In some embodiments, L_(B) is selected from the group consisting ofL_(B57), L_(B58), L_(B61), L_(B67), and L_(A69). In some embodiments,L_(B) is L_(B57). In some embodiments, L_(B) is L_(B58). In someembodiments, L_(B) is L_(B61). In some embodiments, L_(B) is L_(B67). Insome embodiments, L_(B) is L_(B69).

In some embodiments, L_(A) is formula II and L_(B) is formula III. Inembodiments where L_(A) is formula II and L_(B) is formula III, thecompound has the formula I-A:

In the compound of formula I-A, R² and R_(A) are each independentlymono, di, or tri-substitution, or no substitution; R¹, R_(C), and R_(F)are each independently mono, di, tri, or tetra-substitution, or nosubstitution; X¹, X², X³, X⁴, and X⁵ are each independently carbon ornitrogen; R¹, R², R_(A), R_(C), and R_(F) are each independentlyselected from the group consisting of hydrogen, deuterium, halogen,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, and combinations thereof; R³ is selectedfrom the group consisting of alkyl, cycloalkyl, and combinationsthereof; R³ is optionally partially or fully deuterated; and m is 1 or2.

In some embodiments, L_(A) is formula II and L_(B) is formula IV. Inembodiments where L_(A) is formula II and L_(B) is formula IV, thecompound has the formula I-B;

In the compound of formula I-B, R² and R_(D) are each independentlymono, di, or tri-substitution, or no substitution; R¹, R_(B), and R_(F)are each independently mono, di, tri, or tetra-substitution, or nosubstitution; X¹, X², X³, X⁴, and X⁵ are each independently carbon ornitrogen; R¹, R², R_(B), R_(D), and R_(F) are each independentlyselected from the group consisting of hydrogen, deuterium, halogen,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, and combinations thereof; R³ is selectedfrom the group consisting of alkyl, cycloalkyl, and combinationsthereof; R³ is optionally partially or fully deuterated; and m is 1 or2.

In some embodiments, L_(A) is formula II and L_(B) is formula V. Inembodiments where L_(A) is formula II and L_(B) is formula V, thecompound has the formula I-C:

In the compound of formula I-C, R_(E) represents mono ordi-substitution, or no substitution; R² represents mono, di, ortri-substitution, or no substitution; R¹, R_(B), and R_(F) are eachindependently mono, di, tri, or tetra-substitution, or no substitution;X¹, X², X³, and X⁴ are each independently carbon or nitrogen; R¹, R²,R_(B), R_(E), and R_(F) are each independently selected from the groupconsisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl,sulfonyl, phosphino, and combinations thereof; R³ is selected from thegroup consisting of alkyl, cycloalkyl, and combinations thereof; R³ isoptionally partially or fully deuterated; and m is 1 or 2.

In some embodiments, m is 1. In some embodiments, m is 2.

In some embodiments, X is O. In some embodiments, X is S. In someembodiments, X is Se.

In some embodiments, no more than 2 of X¹, X², X³, X⁴, and X⁵ arenitrogen.

In some embodiments, no more than 1 of X¹, X², X³, X⁴, and X⁵ isnitrogen. In some embodiments, X¹, X², X³, X⁴, and X⁵ are carbon.

In some embodiments, R³ is an alkyl having at least 2 carbons. In someembodiments, R³ is an alkyl having at least 3 carbons. In someembodiments, R³ is a cycloalkyl. In some embodiments, R³ is selectedfrom the group consisting of methyl, ethyl, propyl, 1-methylethyl,butyl, 1-methylpropyl, 2-methylpropyl, pentyl, 1-methylbutyl,2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl,2,2-dimethylpropyl, cyclopentyl, and cyclohexyl, wherein each isoptionally partially or fully deuterated.

In some embodiments, R¹ is selected from the group consisting ofhydrogen, deuterium, alkyl, cycloalkyl, and combinations thereof.

In some embodiments, R² represents no substitution.

In some embodiments, R_(F) is selected from the group consisting ofhydrogen, deuterium, alkyl, cycloalkyl, halogen, and combinationsthereof in some embodiments, R_(F) is fluorine.

In some embodiments, R_(C), R_(D), and R_(E) each represent nosubstitution.

In some embodiments, the compound of formula I is selected from thegroup consisting of Compound I-1 to Compound I-15 listed below:

Compound I-15

In some embodiments, the compound of formula I is selected from thegroup consisting of Compound I-16 to Compound I-19 listed below:

In some embodiments, a first device is provided. The first devicecomprises an anode, a cathode, and an organic layer, disposed betweenthe anode and the cathode, comprising a compound having the formula:

(L_(A))_(m)Ir(L_(B))_(3-m)  (I).

In the compound of formula I, L_(A) is

L_(B) is selected from the group consisting of:

R_(E) represents mono or di-substitution, or no substitution; R², R_(A),and R_(D) are each independently mono, di, or tri-substitution, or nosubstitution; R¹, R_(B), R_(C), and R_(F) are each independently mono,di, tri, or tetra-substitution, or no substitution; X¹, X², X³, X⁴, andX⁵ are each independently carbon or nitrogen; X is selected from thegroup consisting of O, S, and Se; R¹, R², R_(A), R_(B), R_(C), R_(D),R_(E), and R_(F) are each independently selected from the groupconsisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl,sulfonyl, phosphino, and combinations thereof; R³ is selected from thegroup consisting of alkyl, cycloalkyl, and combinations thereof; R³ isoptionally partially or fully deuterated; and m is 1 or 2.

In some embodiments, the first device comprises an anode, a cathode, andan organic layer, disposed between the anode and the cathode, comprisinga compound having the formula I-A. In embodiments where L_(A) is formulaII and L_(B) is formula III, the compound has the formula I-A:

In the compound of formula I-A, R² and R_(A) are each independentlymono, di, or tri-substitution, or no substitution; R¹, R_(C), and R_(F)are each independently mono, di, or tetra-substitution, or nosubstitution; X¹, X², X³, X⁴, and X⁵ are each independently carbon ornitrogen; R¹, R², R_(A), R_(C), and R_(F) are each independentlyselected from the group consisting of hydrogen, deuterium, halogen,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, and combinations thereof; R³ is selectedfrom the group consisting of alkyl, cycloalkyl, and combinationsthereof; R³ is optionally partially or fully deuterated; and m is 1 or2.

In some embodiments, the first device comprises an anode, a cathode, andan organic layer, disposed between the anode and the cathode, comprisinga compound having the formula I-B. In embodiments where L_(A) is formulaII and L_(B) is formula IV, the compound has the formula I-B:

In the compound of formula I-B, R² and R_(D) are each independentlymono, di, or tri-substitution, or no substitution; R¹, R_(B), and R_(F)are each independently mono, di, tri, or tetra-substitution, or nosubstitution; X¹, X², X³, X⁴, and X⁵ are each independently carbon ornitrogen; R¹, R², R_(B), R_(D), and R_(F) are each independentlyselected from the group consisting of hydrogen, deuterium, halogen,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, and combinations thereof; R³ is selectedfrom the group consisting of alkyl, cycloalkyl, and combinationsthereof; R³ is optionally partially or fully deuterated; and m is 1 or2.

In some embodiments, the first device comprises an anode, a cathode, andan organic layer, disposed between the anode and the cathode, comprisinga compound having the formula I-C. In embodiments where L_(A) is formulaII and L_(B) is formula V, the compound has the formula I-C:

In the compound of formula I-C, R_(E) represents mono ordi-substitution, or no substitution; R² represents mono, di, ortri-substitution, or no substitution; R¹, R_(B), and R_(F) are eachindependently mono, di, tri, or tetra-substitution, or no substitution;X¹, X², X³, X⁴, and X⁵ are each independently carbon or nitrogen; R¹,R², R_(B), R_(E), and R_(F) are each independently selected from thegroup consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl,sulfonyl, phosphino, and combinations thereof; R³ is selected from thegroup consisting of alkyl, cycloalkyl, and combinations thereof; R³ isoptionally partially or fully deuterated; and m is 1 or 2.

In some embodiments, the first device is a consumer product.

In some embodiments, the first device is an organic light-emittingdevice.

In some embodiments, the first device comprises a lighting panel.

In some embodiments, the organic layer of the first device is anemissive layer and the compound is an emissive dopant. In someembodiments, the organic layer of the first device is an emissive layerand the compound is a non-emissive dopant.

In some embodiments, the organic layer of the first device furthercomprises a host.

In some embodiments, the host of the first device comprises atriphenylene containing benzo-fused thiophene or benzo-fused furan;wherein any substituent in the host is an unfused substituentindependently selected from the group consisting of C_(n)H_(2n+1),OC_(n)H_(2n+1), OAr₁, N(C_(n)H_(2n+1))₂, N(Ar₁)(Ar₂),CH═CH—C_(n)H_(2n+1), Ar₁, Ar₁-Ar₂, C_(n)H_(2n)-Ar₁, or no substitution;wherein n is from 1 to 10; and wherein Ar₁ and Ar₂ are independentlyselected from the group consisting of benzene, biphenyl, naphthalene,triphenylene, carbazole, and heteroaromatic analogs thereof.

In some embodiments, the host of the first device comprises at least onechemical group selected from the group consisting of carbazole,dibenzothiophene, dibenzofuran, dibenzoselenophene, azacarbazole,aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene.

In some embodiments, the host is selected from the group consisting of:

and combinations thereof.

In some embodiments, the host of the first device comprises a metalcomplex.

In some embodiments, a formulation comprising a compound of formula I isprovided.

Combination with Other Materials

The materials described herein as useful for a particular layer in anorganic light emitting device may be used in combination with a widevariety of other materials present in the device. For example, emissivedopants disclosed herein may be used in conjunction with a wide varietyof hosts, transport layers, blocking layers, injection layers,electrodes and other layers that may be present. The materials describedor referred to below are non-limiting examples of materials that may beuseful in combination with the compounds disclosed herein, and one ofskill in the art can readily consult the literature to identify othermaterials that may be useful in combination.

HIL/HTL:

A hole injecting/transporting material to be used in the presentinvention is not particularly limited, and any compound may be used aslong as the compound is typically used as a hole injecting/transportingmaterial. Examples of the material include, but not limit to: aphthalocyanine or porphryin derivative; an aromatic amine derivative; anindolocarbazole derivative; a polymer containing fluorohydrocarbon; apolymer with conductivity dopants; a conducting polymer, such asPEDOT/PSS; a self-assembly monomer derived from compounds such asphosphonic acid and sliane derivatives; a metal oxide derivative, suchas MoO_(x); a p-type semiconducting organic compound, such as1,4,5,8,9,12-Hexaazatriphenylenehexacarbonitrile; a metal complex, and across-linkable compounds.

Examples of aromatic amine derivatives used in HIL or HTL include, butare not limited to the following general structures:

Each of Ar¹ to Ar⁹ is selected from the group consisting aromatichydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl,triphenylene, naphthalene, anthracene, phenalene, phenanthrene,fluorene, pyrene, chrysene, perylene, azulene; group consisting aromaticheterocyclic compounds such as dibenzothiophene, dibenzofuran,dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene,benzoselenophene, carbazole, indolocarbazole, pyridylindole,pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole,oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine,pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine,indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole,benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline,quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine,phenazine, phenothiazine, phenoxazine, benzofuropyridine,furodipyridine, benzothienopyridine, thienodipyridine,benzoselenophenopyridine, and selenophenodipyridine; and groupconsisting 2 to 10 cyclic structural units which are groups of the sametype or different types selected from the aromatic hydrocarbon cyclicgroup and the aromatic heterocyclic group and are bonded to each otherdirectly or via at least one of oxygen atom, nitrogen atom, sulfur atom,silicon atom, phosphorus atom, boron atom, chain structural unit and thealiphatic cyclic group. Wherein each Ar is further substituted by asubstituent selected from the group consisting of hydrogen, deuterium,halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile,sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.

In some embodiments, Ar¹ to Ar⁹ is independently selected from the groupconsisting of:

k is an integer from 1 to 20; X¹⁰¹ to X¹⁰⁸ is C (including CH) or N;Z¹⁰¹ is NAr¹, O, or S; Ar¹ has the same group defined above.

Examples of metal complexes used in HIL or HTL include, but are notlimited to the following general formula:

Met is a metal; (Y¹⁰¹-Y¹⁰²) is a bidentate ligand, Y¹⁰¹ and Y¹⁰² areindependently selected from C, N, O, P, and S; L¹⁰¹ is an anotherligand; k′ is an integer value from 1 to the maximum number of ligandsthat may be attached to the metal; and k′+k″ is the maximum number ofligands that may be attached to the metal.

In some embodiments, (Y¹⁰¹-Y¹⁰²) is a 2-phenylpyridine derivative.

In some embodiments, (Y¹⁰¹-Y¹⁰²) is a carbene ligand.

In some embodiments, Met is selected from Ir, Pt, Os, and Zn.

In a further aspect, the metal complex has a smallest oxidationpotential in solution vs. Fc⁺/Fc couple less than about 0.6 V.

Host:

The light emitting layer of the organic EL device of the presentinvention preferably contains at least a metal complex as light emittingmaterial, and may contain a host material using the metal complex as adopant material. Examples of the host material are not particularlylimited, and any metal complexes or organic compounds may be used aslong as the triplet energy of the host is larger than that of thedopant. While the Table below categorizes host materials as preferredfor devices that emit various colors, any host material may be used withany dopant so long as the triplet criteria is satisfied.

Examples of metal complexes used as host are preferred to have thefollowing general formula:

Met is a metal; (Y¹⁰³-Y¹⁰⁴) is a bidentate ligand, Y¹⁰³ and Y¹⁰⁴ areindependently selected from C, N, O, P, and S; L¹⁰¹ is an anotherligand; k′ is an integer value from 1 to the maximum number of ligandsthat may be attached to the metal; and k′+k″ is the maximum number ofligands that may be attached to the metal.

In some embodiments, the metal complexes are:

(O—N) is a bidentate ligand, having metal coordinated to atoms O and N.

In some embodiments, Met is selected from Ir and Pt.

In a further aspect, (Y¹⁰¹-Y¹⁰⁴) is a carbene ligand.

Examples of organic compounds used as host are selected from the groupconsisting aromatic hydrocarbon cyclic compounds such as benzene,biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene,phenanthrene, fluorene, pyrene, chrysene, perylene, azulene; groupconsisting aromatic heterocyclic compounds such as dibenzothiophene,dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran,benzothiophene, benzoselenophene, carbazole, indolocarbazole,pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole,oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole,pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine,oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine,benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline,cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine,pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine,benzofuropyridine, furodipyridine, benzothienopyridine,thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine;and group consisting 2 to 10 cyclic structural units which are groups ofthe same type or different types selected from the aromatic hydrocarboncyclic group and the aromatic heterocyclic group and are bonded to eachother directly or via at least one of oxygen atom, nitrogen atome,sulfur atom, silicon atom, phosphorus atom, boron atom, chain structuralunit and the aliphatic cyclic group. Wherein each group is furthersubstituted by a substituent selected from the group consisting ofhydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof.

In some embodiments, the host compound contains at least one of thefollowing groups in the molecule:

R¹⁰¹ to R¹⁰⁷ is independently selected from the group consisting ofhydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof, when it is aryl or heteroaryl, it has the similardefinition as Ar's mentioned above.

k is an integer from 1 to 20; k′″ is an integer from 0 to 20.

X¹⁰¹ to X¹⁰⁸ is selected from C (including CH) or N.

Z¹⁰¹ and Z¹⁰² is selected from NR¹⁰¹, O, or S.

HBL:

A hole blocking layer (HBL) may be used to reduce the number of holesand/or excitons that leave the emissive layer. The presence of such ablocking layer in a device may result in substantially higherefficiencies as compared to a similar device lacking a blocking layer.Also, a blocking layer may be used to confine emission to a desiredregion of an OLED.

In some embodiments, compound used in HBL contains the same molecule orthe same functional groups used as host described above.

In some embodiments, compound used in HBL contains at least one of thefollowing groups in the molecule:

k is an integer from 1 to 20; L¹⁰¹ is an another ligand, k′ is aninteger from 1 to 3.

ETL:

Electron transport layer (ETL) may include a material capable oftransporting electrons. Electron transport layer may be intrinsic(undoped), or doped. Doping may be used to enhance conductivity.Examples of the ETL material are not particularly limited, and any metalcomplexes or organic compounds may be used as long as they are typicallyused to transport electrons.

In some embodiments, compound used in ETL contains at least one of thefollowing groups in the molecule:

R¹⁰¹ is selected from the group consisting of hydrogen, deuterium,halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile,sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, whenit is aryl or heteroaryl, it has the similar definition as Ar'smentioned above.

Ar¹ to Ar³ has the similar definition as Ar's mentioned above.

k is an integer from 1 to 20.

X¹⁰¹ to X¹⁰⁸ is selected from C (including CH) or N.

In some embodiments, the metal complexes used in ETL contains, but arenot limited to the following general formula:

(O—N) or (N—N) is a bidentate ligand, having metal coordinated to atomsO, N or N, N; L¹⁰¹ is another ligand; k′ is an integer value from 1 tothe maximum number of ligands that may be attached to the metal.

In any above-mentioned compounds used in each layer of the OLED device,the hydrogen atoms can be partially or fully deuterated. Thus, anyspecifically listed substituent, such as, without limitation, methyl,phenyl, pyridyl, etc. encompasses undeuterated, partially deuterated,and fully deuterated versions thereof. Similarly, classes ofsubstituents such as, without limitation, alkyl, aryl, cycloalkyl,heteroaryl, etc. also encompass undeuterated, partially deuterated, andfully deuterated versions thereof.

In addition to and/or in combination with the materials disclosedherein, many hole injection materials, hole transporting materials, hostmaterials, dopant materials, exiton/hole blocking layer materials,electron transporting and electron injecting materials may be used in anOLED. Non-limiting examples of the materials that may be used in an OLEDin combination with materials disclosed herein are listed in TABLE 3below. TABLE 3 lists non-limiting classes of materials, non-limitingexamples of compounds for each class, and references that disclose thematerials.

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EXPERIMENTAL Compound Examples

Chemical abbreviations used throughout this document are as follows: DMFis dimethylformamide and DCM is dichloromethane.

Example 1 Synthesis of Compound I-1

A mixture of iridium precursor (The synthesis was disclosed inUS2011227049) (2.5 g, 3.37 mmol),8-(4-(4-fluorophenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(2.15 g, 6.07 mmol), 2-ethoxyethanol (40 mL), and DMF (40 mL) was heatedat 130° C. overnight. The solvent mixture was evaporated under vacuum.The residue was run through a short silica plug. The mixture obtainedwas further purified by silica gel column with DCM/Heptane as eluent toobtain Compound I-1 (1.8 g, 60.6% yield) which was confirmed by LC-MS.

Example 2 Synthesis of Compound I-2

A mixture of iridium precursor (2.5 g, 3.25 mmol),8-(4-(4-fluorophenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(2.071 g, 5.85 mmol), 2-ethoxyethanol (40 mL), and DMF (40 mL) washeated at 130° C. overnight. The solvent mixture was evaporated undervacuum. The residue was run through a short silica plug. The mixtureobtained was further purified by silica gel column with DCM/Heptane aseluent to obtain Compound I-2 (1.88 g, 63.6% yield) which was confirmedby LC-MS.

Example 3 Synthesis of Compound I-3

A mixture of iridium precursor (2.5 g, 3.25 mmol),8-(5-(4-fluorophenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(2.071 g, 5.85 mmol), 2-ethoxyethanol (40 mL), and DMF (40 mL) washeated at 130° C. overnight. The solvent mixture was evaporated undervacuum. The residue was run through a short silica plug. The mixtureobtained was further purified by silica gel column with DCM/Heptane aseluent to obtain Compound I-3 (1.75 g, 59.2% yield) which was confirmedby LC-MS.

Example 4 Synthesis of Compound I-4

A mixture of iridium precursor (2.0 g, 2.507 mmol),8-(4-(4-fluorophenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(1.599 g, 4.51 mmol), 2-ethoxyethanol (25 mL), and DMF (25 mL) washeated at 130° C. overnight. The solvent mixture was evaporated undervacuum. The residue was run through a short silica plug. The mixtureobtained was further purified by silica gel column with DCM/Heptane aseluent to obtain Compound I-4 (1.18 g, 50.2% yield) which was confirmedby LC-MS.

Example 5 Synthesis of Compound I-5

A mixture of iridium precursor (1.55 g, 1.943 mmol),8-(4-(4-isobutylphenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(1.525 g, 3.89 mmol), and ethanol (60 mL) was heated at 85° C. for 3days. The solvent mixture was evaporated under vacuum. The residue wasrun through a short silica plug. The mixture obtained was furtherpurified by silica gel column with DCM/Heptane as eluent to obtainCompound I-5 (1.0 g, 52.7% yield) which was confirmed by LC-MS.

Example 6 Synthesis of Compound I-6

A mixture of iridium precursor (2.2 g, 2.76 mmol),2-methyl-8-(4-phenylpyridin-2-yl)benzofuro[2,3-b]pyridine (1.669 g, 4.96mmol), and ethanol (100 mL) was heated at 85° C. for 3 days. The solventmixture was evaporated under vacuum. The residue was run through a shortsilica plug. The mixture obtained was further purified by silica gelcolumn with DCM/Heptane as eluent to obtain Compound I-6 (1.1 g, 43.4%yield) which was confirmed by LC-MS.

Example 7 Synthesis of Compound I-7

A mixture of iridium complex (1.8 g, 2.256 mmol),8-(4-(4-fluoro-3-isobutylphenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(1.482 g, 4.51 mmol), 2-ethoxyethanol (40 mL) and DMF (40 mL) was heatedat 130° C. overnight. The solvent mixture was evaporated under vacuum.The residue was run through a short silica plug. The mixture obtainedwas further purified by silica gel column with DCM/Heptane as eluent toobtain Compound I-7 (1.00 g, 44.6% yield) which was confirmed by LC-MS.

Example 8 Synthesis of Compound I-8

8-(4-(4-fluoro-3,5-diisopropylphenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(2.325 g, 5.30 mmol) and the iridium precursor (2.35 g, 2.95 mmol) werecharged into the reaction flask with 40 mL of DMF and 40 mL of2-ethoxyethanol. This mixture was degassed with nitrogen then was heatedin an oil bath set at 130° C. for 18 hours. The solvents were removedunder vacuum. The crude residue was passed through a silica gel plug.This crude residue was passed through a silica gel column usingDCM/heptanes to elute the column. The clean fractions were combined andconcentrated under vacuum yielding Compound I-8 (1.6 g, 53.1% yield) asan orange solid. LC/MS analysis confirmed the mass for the desiredproduct.

Example 9 Synthesis of Compound I-9

A mixture of iridium precursor (2.5 g, 3.13 mmol),8-(5-(4-fluorophenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(1.99 g, 5.64 mmol), 2-ethoxyethanol (30 mL), and DMF (30 mL) was heatedat 130° C. overnight. The solvent mixture was evaporated under vacuum.The residue was run through a short silica plug. The mixture obtainedwas further purified by silica gel column with DCM as eluent to obtainCompound I-9 (1.6 g, 57.5% yield) which was confirmed by LC-MS.

Example 10 Synthesis of Compound I-10

A mixture of iridium precursor (2.5 g, 3.03 mmol),8-(4-(4-fluorophenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(1.931 g, 5.45 mmol), and ethanol (100 mL) was heated at 85° C. for 3days. The solvent mixture was evaporated under vacuum. The residue wasrun through a short silica plug. The mixture obtained was furtherpurified by silica gel column with DCM/Heptane as eluent to obtainCompound I-10 (1.3 g, 44.5% yield) which was confirmed by LC-MS.

Example 11 Synthesis of Compound I-11

A mixture of iridium precursor (2.5 g, 3.03 mmol),8-(4-(4-isobutylphenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(2.138 g, 5.45 mmol), and ethanol (100 mL) was heated at 85° C. for 3days. The solvent mixture was evaporated under vacuum. The residue wasran through a short silica plug. The mixture obtained was furtherpurified by silica gel column with DCM/Heptane as eluent to obtainCompound I-11 (2.3 g, 76.0% yield) which was confirmed by LC-MS.

Example 12 Synthesis of Compound I-12

A mixture of iridium precursor (1.9 g, 2.30 mmol),8-(4-(4-fluoro-3-isobutylphenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(1.51 g, 3.68 mmol), 2-ethoxyethanol (40 mL), and DMF (40 mL) was heatedat 130° C. overnight. The solvent mixture was evaporated under vacuum.The residue was run through a short silica plug. The mixture obtainedwas further purified by silica gel column with DCM/Heptane as eluent toobtain Compound I-12 (1.5 g, 63.8% yield) which was confirmed by LC-MS.

Example 13 Synthesis of Compound I-13

A mixture of iridium precursor (2.5 g, 3.03 mmol),8-(4-(4-fluorophenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(1.931 g, 5.45 mmol), and ethanol (120 mL) was heated at 85° C. for 3days. The solvent mixture was evaporated under vacuum. The residue wasrun through a short silica plug. The mixture obtained was furtherpurified by silica gel column with DCM/Heptane as eluent to obtainCompound I-13 (0.75 g, 25.7% yield) which was confirmed by LC-MS.

Example 14 Synthesis of Compound I-14

8-(4-(4-fluorophenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(1.740 g, 4.91 mmol) and the iridium precursor (2.1 g, 2.73 mmol) werecharged into the reaction flask with 100 mL of ethanol. This mixture wasdegassed with nitrogen then was heated at reflux for 3 days. Thesolvents were removed under vacuum. The crude residue was passed througha silica gel plug. The filtrate was concentrated under vacuum. Thiscrude residue was passed through a silica gel column using DCM/heptanesto elute the column. The clean fractions were combined and concentratedunder vacuum yielding Compound I-14 (0.9 g, 36.3% yield) as an orangesolid. LC/MS analysis confirmed the mass for the desired product.

Example 15 Synthesis of Compound I-15

8-(4-(4-fluorophenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(1.876 g, 5.29 mmol) and iridium precursor (2.5 g, 2.94 mmol) werecharged into the reaction flask with 100 mL of ethanol. This reactionmixture was degassed with nitrogen then was heated in an oil bath set at85° C. for 3 days. Heating was discontinued. The reaction mixture wasconcentrated under vacuum. The crude product was dissolved in DCM andwas passed through a silica gel plug. This crude product was then passedthrough 2×300 g silica gel columns eluting with DCM/Heptanes. Cleanproduct fractions were combined and concentrated under vacuum yieldingCompound I-15 (1.52 g, 52.2% yield) as an orange solid. LC/MS analysisconfirmed the mass for the desired product.

Example 16 Synthesis of Compound I-16

The iridium precursor (2.0 g, 2.342 mmol),8-(4-(4-fluorophenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(1.494 g, 4.22 mmol), DMF 25 mL and 2-ethoxyethanol 25 mL were combinedin a 250 mL single neck round bottom flask. A condenser was attachedthen the system was evacuated and purged with nitrogen three times. Thereaction was heated in an oil bath set at 130° C. overnight. Thereaction was concentrated down to an orange sludgy solid. The solid waspartially dissolved in 200 mL hot DCM and filtered through 200 mg silicagel in fitted Buchner funnel with DCM. The filtrate was concentrateddown to 0.84 g of an orange solid. The 0.84 g sample was purified withsilica gel using a 75/25 to 25/75 heptane/DCM solvent system to get 0.45g to an orange-yellow solid for a 19.3% yield. HPLC indicated 99.7%purity and LC/MS indicated it has the correct mass.

Example 17 Synthesis of Compound I-17

A mixture of iridium precursor (2.3 g, 2.69 mmol),8-(4-(4-fluorophenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(1.72 g, 4.85 mmol), 2-ethoxyethanol (40 mL) and DMF (40 mL) was heatedat 130° C. overnight. The reaction mixture was concentrated to removesolvents and filtered through a small plug of silica gel and furtherchromatographed to give 0.69 g desired product (26% yield).

Example 18 Synthesis of Compound I-18

A mixture of iridium precursor (1.3 g, 1.37 mmol),2-methyl-8-(pyridin-2-yl)benzofuro[2,3-b]pyridine-d₆ (0.65 g, 2.46mmol), 2-ethoxyethanol (20 mL) and DMF (20 mL) was heated at 130° C.overnight. The reaction mixture was concentrated to remove solvents andfiltered through a small plug of silica gel and further chromatographedto give 0.76 g desired product (55% yield). (1.52 g, 52.2% yield) as anorange solid. LC/MS analysis confirmed the mass for the desired product.

Example 19 Synthesis of Compound I-19

The iridium precursor (2.5 g, 2.93 mmol),8-(4-(4-fluorophenyl)pyridin-2-yl)-2-methylbenzofuro[2,3-b]pyridine(1.867 g, 5.27 mmol), DMF 25 mL and 2-ethoxyethanol 25.0 mL werecombined in a 250 ml single neck round bottom flask. A condenser wasattached then the system was evacuated and purged with nitrogen threetimes. The reaction was heated in an oil bath set at 130° C. overnight.The reaction was concentrated down to an orange sludgy solid. The solidwas dissolved in 100 ml DCM and filtered through 200 g silica gel infritted Buchner funnel with DCM. The filtrate was concentrated down to2.3 g of an orange solid. The solid was further purified with silica gelusing 25/75 to 15/85 heptane/DCM solvent system to get 0.75 g of anorange-yellow solid (25.8% yield). HPLC indicated 99.5% purity at 254 nmand LC/MS indicated it has the correct mass.

Device Examples

All example devices were fabricated by high vacuum (<10⁻⁷ Torr) thermalevaporation. The anode electrode is 1200 Å of indium tin oxide (ITO).The cathode consisted of 10 Å of LiF followed by 1,000 Å of Al. Alldevices are encapsulated with a glass lid sealed with an epoxy resin ina nitrogen glove box (<1 ppm of H₂O and O₂) immediately afterfabrication, and a moisture getter was incorporated inside the package.

The organic stack of the device examples consisted of sequentially, fromthe ITO surface, 100 Å of Compound B as the hole injection layer (HIL),300 Å of 4,4% bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD) as thehole transporting layer (HTL), 300 Å of the invention compound doped inCompound C as host with as the emissive layer (EML), 50 Å of Compound Cas blocking layer 450 Å of Alq₃ (tris-8-hydroxyquinoline aluminum) asthe ETL. Comparative Example with Compound A was fabricated similarly tothe Device Examples except that the Compound A was used as the emitterin the EML.

The device results and data are summarized in Tables 1 and 2 from thosedevices. As used herein, NPD, Alq, Compound A, Compound B, and CompoundC have the following structures:

TABLE 2 DEVICE EXAMPLES DEVICE EXAMPLE HIL HTL EML (300 Å, doping %) BLETL Comparative Compound B NPD 300 Å Compound C Compound A Compound CAlq 450 Å Example 1 100 Å 7% 50 Å Inventive Compound B NPD 300 ÅCompound C Compound I-2 Compound C Alq 450 Å Example 1 100 Å 7% 50 ÅInventive Compound B NPD 300 Å Compound C Compound I-4 Compound C Alq450 Å Example 2 100 Å 7% 50 Å

TABLE 3 VACUUM THERMAL EVAPORATION CIE λ max FWHM Example x y [nm] [nm]EQE Comparative 0.42 0.57 548 71 20.9 Example 1 Inventive 0.45 0.55 55574 24.7 Example 1 Inventive 0.45 0.55 554 74 22.3 Example 2

Table 3 summarizes the performance of the devices. External quantumefficiency (EQE) was measured at 1000 nits. As shown in Table 3 thedevice prepared using Compound I-2 and Compound I-4 of the presentinvention showed similar color to the device prepared using comparativeCompound A. However, the EQE of the devices with Compound I-2 andCompound I-4 was much higher than the device with comparative CompoundA. Therefore, devices prepared with compounds containing an alkyl groupat the 4-position of the phenyl ring in the phenylpyridine showed muchhigher EQEs than a compound that contained a hydrogen at this position.

It is understood that the various embodiments described herein are byway of example only, and are not intended to limit the scope of theinvention. For example, many of the materials and structures describedherein may be substituted with other materials and structures withoutdeviating from the spirit of the invention. The present invention asclaimed may therefore include variations from the particular examplesand preferred embodiments described herein, as will be apparent to oneof skill in the art it is understood that various theories as to why theinvention works are not intended to be limiting.

What is claimed is:
 1. A compound having the formula(L_(A))_(m)Ir(L_(B))_(3-m)  (I); wherein L_(A) is

wherein L_(B) is selected from the group consisting of:

wherein R_(E) represents mono or di-substitution, or no substitution;wherein R², R_(A), and R_(D) are each independently mono, di, ortri-substitution, or no substitution; wherein R¹, R_(B), R_(C), andR_(F) are each independently mono, di, tri, or tetra-substitution, or nosubstitution; wherein X¹, X², X³, X⁴, and X⁵ are each independentlycarbon or nitrogen; wherein X is selected from the group consisting ofO, S, and Se; wherein R¹, R², R_(A), R_(B), R_(C), R_(D), R_(E), andR_(F) are each independently selected from the group consisting ofhydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof; wherein R³ is selected from the group consistingof alkyl, cycloalkyl, and combinations thereof; wherein R³ is optionallypartially or fully deuterated; and wherein m is 1 or
 2. 2. The compoundof claim 1, wherein m is
 2. 3. The compound of claim 1, wherein X is O.4. The compound of claim 1, wherein R³ is an alkyl having at least 2carbons.
 5. The compound of claim 1, wherein R³ is an alkyl having atleast 3 carbons.
 6. The compound of claim 1, wherein R³ is a cycloalkyl.7. The compound of claim 1, wherein R³ is selected from the groupconsisting of methyl, ethyl, propyl, 1-methylethyl, butyl,1-methylpropyl, 2-methylpropyl, pentyl, 1-methylbutyl, 2-methylbutyl,3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl,2,2-dimethylpropyl, cyclopentyl, and cyclohexyl, wherein each isoptionally partially or fully deuterated.
 8. The compound of claim 1,wherein R¹ is selected from the group consisting of hydrogen, deuterium,alkyl, cycloalkyl, and combinations thereof.
 9. The compound of claim 1,wherein R² represents no substitution.
 10. The compound of claim 1,wherein R_(F) is selected from the group consisting of hydrogen,deuterium, alkyl, cycloalkyl, halogen, and combinations thereof.
 11. Thecompound of claim 1, wherein R_(F) is fluorine.
 12. The compound ofclaim 1, wherein R_(C), R_(D), and R_(E) each represent no substitution.13. The compound of claim 1, wherein L_(B) is selected from the groupconsisting of:


14. The compound of claim 1, wherein L_(B) is:

wherein R_(G) represents mono, di, tri, or tetra-substitution, or nosubstitution; and wherein R_(G) is selected from the group consisting ofhydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof.
 15. The compound of claim 14, wherein R_(B) andR_(E) represent no substitution; and wherein R_(F) and R_(G) are eachindependently selected from the group consisting of hydrogen, deuterium,alkyl, cycloalkyl, halogen, and combinations thereof.
 16. The compoundof claim 15, wherein R_(G) is fluorine.
 17. The compound of claim 1,wherein L_(A) is selected from the group consisting of:


18. The compound of claim 1, wherein L_(A) is selected from the groupconsisting of:


19. The compound of claim 1, wherein L_(B) is selected from the groupconsisting of:


20. The compound of claim 1, wherein the compound is selected from thegroup consisting of:


21. The compound of claim 1, wherein the compound is selected from thegroup consisting of:


22. A first device comprising a first organic light emitting device, thefirst organic light emitting device comprising: an anode; a cathode; andan organic layer, disposed between the anode and the cathode, comprisinga compound having the formula:(L)_(m)Ir(L_(B))_(3-m)  (I); wherein L_(A) is

wherein L_(B) is selected from the group consisting of:

wherein R_(E) represents mono or di-substitution, or no substitution;R², R_(A), and R_(D) are each independently mono, di, ortri-substitution, or no substitution; wherein R¹, R_(B), R_(C), andR_(F) are each independently mono, di, tri, or tetra-substitution, or nosubstitution; wherein X¹, X², X³, X⁴, and X⁵ are each independentlycarbon or nitrogen; wherein X is selected from the group consisting ofO, S, and Se; wherein R¹, R², R_(A), R_(B), R_(C), R_(D), R_(E), andR_(F) are each independently selected from the group consisting ofhydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof; wherein R³ is selected from the group consistingof alkyl, cycloalkyl, and combinations thereof; wherein R³ is optionallypartially or fully deuterated; and wherein m is 1 or
 2. 23. The firstdevice of claim 22, wherein the organic layer is an emissive layer andthe compound is an emissive dopant.
 24. A formulation comprising acompound of claim 1.